1. Field of the Invention
The present invention relates to a power transmission mechanism for a turret of a lathe, more particularly one equipped with a force multiplier unit, which includes several steel beads used for pushing a tool disk of the lathe, and several sloping trenches used for guiding the beads such that the tool disk can be pushed to a secured position by the beads with multiplied force output, and such that an air pressure power source can be used instead of a hydraulic power source while the force output is enough for making the tool disk effectively secured in position.
2. Brief Description of the Prior Art
Referring to FIG. 6, a conventional turret 2 of a lathe includes a shaft housing 21, a central shaft 22 in the shaft housing 21, a piston 23, and a clutch 24; the central shaft 22 has a step-shaped portion 221, and a gear 222 secured thereon; oil passages 231, and 232 of a hydraulic system are provided so that the piston 23 can be left and right displaced by means of hydraulic oil; the piston 23 is positioned between the step-shaped portion 221 of the central shaft 22 and the gear 222; the clutch 24 is fitted to the shaft housing 21. Furthermore, a tool disk 3 is securely joined to one end of the central shaft 22 next to the clutch 24. Thus, when the piston 23 is moved rightwards by means of hydraulic oil supplied through the oil passage 231, the central shaft 22 will be made to move rightwards together with the gear 222, and in turns, the tool disk 3 will be engaged with the clutch 24, and secured in position. When the piston 23 is moved leftwards by means of hydraulic oil supplied through the oil passage 232, the central shaft 22 will be pushed leftwards at the step-shaped portion 221 by the piston 23, and in turns, the tool disk 3 will disengage the clutch 24, and can be turned for switching one tool to another.
Enough power can be provided for moving the tool disk 3 between the engaged position and the disengaged one with the help of the hydraulic system and the oil passages, but conventional hydraulic systems have some disadvantages, which also exist in the above structure, as compared with air pressure means, e.g. high manufacturing cost, oil leakage, high maintenance cost, and high power consumption. However, it is also infeasible to replace the hydraulic system with an air pressure means because an air pressure means has to have larger dimensions than the hydraulic system to provide the same power output as the hydraulic system, and increase to dimensions will cause increase to both cost and weight.